As an alternative to animal box litters made of clay, a variety of other commonly available natural materials have been utilized for purposes of absorption and deodorization of animal wastes. For example, wood shavings, sawdust, and alfalfa have been marketed for this use, however, each of these materials is easily dampened and slow to dry, thereby creating a favorable breeding environment for microorganisms. Moreover, such animal litter materials generally have little capacity for neutralizing and eliminating the unpleasant odors associated with animal wastes. Furthermore, these materials readily breakdown into a dust which is ineffective as an absorbent.
To alleviate the dust problem, these prior art animal box litter materials have been further processed by extrusion, compression, and the inclusion of binding agents in order to formulate pellets which are physically more durable. Binding agents such as molasses, glue, and starch have been used to this end in the prior art (see U.S. Pat. No. 3,789,797 to Brewer).
In order to mask the unpleasant odors of animal waste, fragrances have been added to the prior art litter, the fragrances becoming activated in the presence of moisture such as cat urine (see U.S. Pat. No. 3,675,625 to Miller et. al.). However, such fragrances can be rapidly lost by volatilization when the litter is in continuous use or during extended storage.
In addition, deodorizers such as chlorophyll and baking soda have been tried, but these additives have an inherently low odor absorption capacity which is further diminished by environmental factors such as high humidity and temperature (see U.S. Pat. No. 4,203,388 to Cortigene et. al.).
Antibacterial agents (bactericides) such as quaternary ammonia salts and sodium propionate have also been added to the litter to prevent the development of unpleasant odors by arresting the growth of odor-causing bacteria and fungi in the litter box (see U.S. Pat. No. 3,828,731 to White). In addition, these bactericides function to minimize the decomposition of the natural litter material (usually fibrous plant matter) as well.